5-Methyl-1,2-oxazole-3-carb­oxy­lic acid

Abstract

In the crystal structure of the title compound, C₅H₅NO₃, all the non-H atoms are approximately coplanar: the carb­oxy O atoms deviating by 0.013 (2) and −0.075 (2) Å from the isoxazole ring plane. In the crystal, the molecules form inversion dimers linked by pairs of O—H⋯O hydrogen bonds and the dimers stack via π–π inter­actions [centroid–centroid distance = 3.234 (2) Å].

Related literature

The title compound is a potent inhibitor of the monoamine oxidase enzyme and multidentate ligand for transition metals, see: Birk & Weihe (2009 ▶).

Experimental

Crystal data

• C₅H₅NO₃

• M _r = 127.10

• Triclinic,

• a = 4.9125 (10) Å

• b = 5.6909 (11) Å

• c = 10.464 (2) Å

• α = 82.21 (3)°

• β = 79.72 (3)°

• γ = 78.96 (3)°

• V = 280.96 (10) ų

• Z = 2

• Mo Kα radiation

• μ = 0.13 mm⁻¹

• T = 293 K

• 0.20 × 0.20 × 0.20 mm

Data collection

• Rigaku SCXmini diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.975, T _max = 0.975

• 2923 measured reflections

• 1283 independent reflections

• 1052 reflections with I > 2σ(I)

• R _int = 0.079

Refinement

• R[F ² > 2σ(F ²)] = 0.084

• wR(F ²) = 0.230

• S = 1.07

• 1283 reflections

• 83 parameters

• 1 restraint

• H-atom parameters constrained

• Δρ_max = 0.31 e Å⁻³

• Δρ_min = −0.41 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶), ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Supplementary material file. DOI: 10.1107/S160053681103532X/jh2316Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O1i	0.98	1.68	2.650 (2)	170

Symmetry code: (i) .

supplementary crystallographic information

Comment

5-Methylisoxazole-3-carboxylic acid is a potent inhibitor of the monoamine oxidase enzyme and excellent ligand for transition metals (Birk, et al.,2009) as well as other derivatives of isoxazole. As part of our interest in these compounds, we report here the crystal structure of the title compound.

The molecular structure of the title compound is shown in Fig. 1. All the non-H atoms of the title compound are located almost in one plane, as the atoms O1 and O2 are shifted just ca 0.0016Å out of the isoxazole ring plane.

The title compound formed dimer via intermolecular O—H···O hydrogen bonds and the dimers packed viaπ–π stacking interactions (3.234 Å).(Fig. 2).

Experimental

The title compound was purchased commercially. Crystals suitable for X-ray diffraction were obtained by slow evaporation of an ethanol solution.

Refinement

All H atoms attached to C atoms and O atoms were fixed geometrically and treated as riding with C—H = 0.93 Å (CH) or C—H = 0.96 Å and O—H = 0.9796 Å with U_iso(H) = 1.2U_eq(CH) and U_iso(H) = 1.5U_eq(O,CH₃).

Figures

Fig. 1.

The molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii.

Fig. 2.

A packing view down the a axis showing the three dimensionnal network.Intermolecular hydrogen bonds are shown as dashed lines. H atoms have been omitted for the sake of clarity.

Crystal data

C5H5NO3	Z = 2
Mr = 127.10	F(000) = 132
Triclinic, P1	Dx = 1.502 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.9125 (10) Å	Cell parameters from 1283 reflections
b = 5.6909 (11) Å	θ = 3.7–27.5°
c = 10.464 (2) Å	µ = 0.13 mm−1
α = 82.21 (3)°	T = 293 K
β = 79.72 (3)°	Prism, colourless
γ = 78.96 (3)°	0.20 × 0.20 × 0.20 mm
V = 280.96 (10) Å3

Data collection

Rigaku SCXmini diffractometer	1283 independent reflections
Radiation source: fine-focus sealed tube	1052 reflections with I > 2σ(I)
graphite	Rint = 0.079
Detector resolution: 13.6612 pixels mm-1	θmax = 27.5°, θmin = 3.7°
CCD_Profile_fitting scans	h = −6→6
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −7→7
Tmin = 0.975, Tmax = 0.975	l = −13→13
2923 measured reflections

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.084	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.230	H-atom parameters constrained
S = 1.07	w = 1/[σ2(Fo2) + (0.1395P)2] where P = (Fo2 + 2Fc2)/3
1283 reflections	(Δ/σ)max < 0.001
83 parameters	Δρmax = 0.31 e Å−3
1 restraint	Δρmin = −0.41 e Å−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O3	−0.2313 (3)	0.3175 (2)	0.15660 (15)	0.0539 (5)
N1	−0.0692 (4)	0.1507 (3)	0.2343 (2)	0.0530 (6)
C2	0.0502 (4)	0.2811 (3)	0.29544 (17)	0.0401 (5)
C1	0.2432 (4)	0.1560 (3)	0.38652 (18)	0.0419 (5)
C3	−0.0274 (4)	0.5290 (3)	0.26092 (19)	0.0436 (5)
H3	0.0293	0.6551	0.2915	0.052*
C4	−0.2024 (4)	0.5436 (3)	0.17357 (18)	0.0428 (5)
O1	0.2945 (3)	−0.0687 (3)	0.40024 (16)	0.0560 (5)
C5	−0.3597 (5)	0.7439 (4)	0.0956 (2)	0.0541 (6)
H5A	−0.3371	0.7068	0.0071	0.081*
H5B	−0.2886	0.8892	0.0971	0.081*
H5C	−0.5553	0.7655	0.1323	0.081*
O2	0.3450 (3)	0.2937 (2)	0.44412 (15)	0.0551 (5)
H2	0.4849 (14)	0.1977 (10)	0.4948 (5)	0.083*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O3	0.0681 (10)	0.0405 (9)	0.0617 (10)	−0.0087 (7)	−0.0357 (8)	−0.0030 (7)
N1	0.0638 (11)	0.0374 (10)	0.0650 (12)	−0.0080 (8)	−0.0332 (9)	−0.0017 (8)
C2	0.0447 (10)	0.0375 (10)	0.0398 (10)	−0.0074 (7)	−0.0116 (8)	−0.0032 (8)
C1	0.0446 (10)	0.0415 (10)	0.0408 (10)	−0.0082 (8)	−0.0103 (8)	−0.0028 (8)
C3	0.0496 (11)	0.0391 (11)	0.0455 (10)	−0.0088 (8)	−0.0139 (8)	−0.0058 (8)
C4	0.0495 (10)	0.0362 (10)	0.0446 (10)	−0.0066 (8)	−0.0137 (8)	−0.0036 (7)
O1	0.0646 (10)	0.0407 (9)	0.0655 (10)	−0.0029 (7)	−0.0291 (8)	0.0015 (7)
C5	0.0625 (13)	0.0463 (12)	0.0540 (12)	−0.0031 (9)	−0.0220 (10)	0.0009 (9)
O2	0.0624 (10)	0.0517 (10)	0.0581 (10)	−0.0081 (8)	−0.0295 (8)	−0.0057 (7)

Geometric parameters (Å, °)

O3—C4	1.359 (2)	C3—C4	1.347 (3)
O3—N1	1.388 (2)	C3—H3	0.9300
N1—C2	1.317 (3)	C4—C5	1.482 (3)
C2—C3	1.404 (3)	C5—H5A	0.9600
C2—C1	1.481 (3)	C5—H5B	0.9600
C1—O1	1.249 (2)	C5—H5C	0.9600
C1—O2	1.270 (2)	O2—H2	0.9796
C4—O3—N1	109.46 (15)	C3—C4—O3	108.95 (18)
C2—N1—O3	104.75 (15)	C3—C4—C5	134.7 (2)
N1—C2—C3	112.28 (18)	O3—C4—C5	116.31 (18)
N1—C2—C1	118.65 (18)	C4—C5—H5A	109.6
C3—C2—C1	129.06 (18)	C4—C5—H5B	109.4
O1—C1—O2	125.6 (2)	H5A—C5—H5B	109.5
O1—C1—C2	119.38 (18)	C4—C5—H5C	109.5
O2—C1—C2	114.99 (17)	H5A—C5—H5C	109.5
C4—C3—C2	104.56 (17)	H5B—C5—H5C	109.5
C4—C3—H3	127.7	C1—O2—H2	109.6
C2—C3—H3	127.8

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1i	0.98	1.68	2.650 (2)	170.

Symmetry codes: (i) −x+1, −y, −z+1.